CVE-2026-74683

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

Input: evdev - sanitize event type index when fetching event masks

The user-supplied event type index passed to EVIOCGMASK / EVIOCSMASK

ioctls is used to index the static counts array in evdev_get_mask_cnt()

and client evmasks array in evdev_get_mask().

While the event type is architecturally bounded by EV_CNT, speculative

execution may mispredict bounds checks and perform out-of-bounds loads.

Sanitize the event type index in evdev_get_mask_cnt() branchlessly using

array_index_mask_nospec(). This clamps the index to 0 for safe array

access and forces the returned count to 0 speculatively when the index

is out of bounds.

We do not need additional array_index_nospec() calls in evdev_get_mask()

because evdev_get_mask_cnt() speculatively forces the count (and

resulting xfer_size) to 0 for out-of-bounds types, preventing any

speculative memory access to client evmasks array.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References